1. Field of the Invention
The present invention relates generally to computer graphics imagery, and more specifically, toward the simulation of motion blur in computer generated imagery.
2. Related Art
Individual frames within a sequence of frames recorded using standard video and film cameras often contain noticeable blurring of moving objects. This blurring is rarely noticeable when these frames are played back at the same rate at which they were recorded. A viewer uses the blurriness of the object in the individual frames to make assumptions about its relative velocity and predictions about its position in subsequent frames.
In computer generated animation, on the other hand, a frame is typically generated by sampling an application model at an instant of time. Effectively, the sampling model simulates an instantaneous shutter on a video camera. This form of sampling is satisfactory with scenes of low and moderate action. However, unpleasant stroboscopic effects (e.g., jerkiness) are evident when rapidly moving objects are present. This results since computer generated animation lacks the real-world motion blur of a moving object.
To compensate for these deficiencies, simulated motion blur is used in computer generated imagery to mitigate visually objectionable artifacts that result from the discrete nature of sampling. Motion blur simulations enable an animator to recreate the short-duration exposure intervals of real-world video shutters. Seamless integration of animation and real-world footage can therefore occur. The perceived realism of these integrations will continue to increase as the motion blur simulations improve. Since the simulation of motion blur is computationally expensive, what is needed is an efficient method for handling motion blur in large scenes having arbitrary shaders, textures, transparent objects and surface tessellations (e.g., a polygon mesh).